Per- and polyfluoroalkyl substances (PFAS) have existed for over 70 years, being used in the manufacturing of everything from non-stick cookware to firefighting foams to dental floss. With its continued prevalence in the market and hard-to-degrade nature, PFAS is almost unavoidable and can be found in most environmental matrices, including air, water, and soil. This has led to an increased need in research regarding the concentration of PFAS in the environment to provide insight into current and legacy levels of contamination and to establish monitoring to detect fluctuations in such levels. Equally important is measuring trace amounts of PFAS in the environment as recent years have led to the discovery that even low levels of exposure can negatively impact human health and easily accumulate in the environment and the body.

The PFAS Research Center at the Wisconsin State Lab of Hygiene is one of the only groups in the nation that can detect low levels of PFAS in environmental samples using non-targeted combustion ion chromatography (CIC). Combustion ion chromatography retains the specificity and sensitivity of traditional ion chromatography while allowing for the testing of all types of combustible samples. In CIC, samples undergo pyrohydrolysis at a temperature of 1050 degrees C in a combustion oven, where total organic fluorine in the sample will become gaseous HF. The HF is transferred to the absorber module where it is brought into solution for matrix elimination, and then this solution is injected into the IC system for analysis.

In order to conduct low-level work, we use a combination of pre-analytic SPE to concentration our samples 1000-fold, a preconcentration column within the CIC instrument to further concentrate samples, and repeated check standards within a run to capture any corrections to be made post-analysis. This allows us to report accurate and precise data for projects such as precipitation, groundwater, and surface water monitoring that may have total organic fluorine concentrations in the low parts per billion. In addition to low-level work, we have also handled a wide range of investigative work with projects that include AFFF, well-drilling foams, impinger samples, septage, and leachates that range from being in the very high parts per million to having no trace of total organic fluorine at all.

In this presentation, we will be going over the CIC instrumentation and methods used at the PFAS Research Center, improvements we have made along the way, and data from select projects.

¹ Wisconsin State Lab of Hygiene, Madison, WI

* Corresponding Author: iris.bloede@slh.wisc.edu